Methods, devices, and computer-readable media for preventing broadcast loops during a site merge

Abstract

Methods, devices, and computer-readable medium for preventing broadcast looping during a site merge are described herein. An example method can include detecting a site merge between a plurality of layer 2 (L2) networks using a spanning tree protocol (STP), blocking a data traffic port connecting the L2 networks in response to detecting the site merge, and performing an STP-Ethernet virtual private network (EVPN) handshake. The STP-EVPN handshake can include changing a root bridge in one of the L2 networks. Thereafter, the method can include unblocking the data traffic port connecting the L2 networks. In other words, the data traffic port connecting the L2 networks can be unblocked after changing the root bridge in the one of the L2 networks.

What is claimed: 
     
       1. A method for preventing broadcast looping in a network, comprising:
 detecting a site merge between a plurality of layer 2 (L2) networks using a spanning tree protocol (STP); 
 blocking a data traffic port connecting the L2 networks in response to detecting the site merge; 
 performing an STP-Ethernet virtual private network (EVPN) handshake, wherein the STP-EVPN handshake comprises:
 notifying a plurality of virtual private network (VPN) devices connected to the merged site of a request to change a root bridge in one of the L2 networks, 
 changing the root bridge in the one of the L2 networks, and 
 receiving acknowledgement after changing the root bridge in the one of the L2 networks; and 
 
 unblocking the data traffic port connecting the L2 networks, wherein detecting the site merge between the L2 networks using the STP comprises detecting presence of different root bridges for the L2 networks. 
 
     
     
       2. The method of  claim 1 , wherein the data traffic port connecting the L2 networks is unblocked after changing the root bridge in the one of the L2 networks. 
     
     
       3. The method of  claim 1 , wherein the STP-EVPN handshake is performed by exchanging STP messages with the VPN devices connected to the merged site. 
     
     
       4. The method of  claim 1 , further comprising:
 calculating a new spanning tree for the merged site; and 
 selecting a root bridge for the merged site. 
 
     
     
       5. The method of  claim 4 , further comprising updating respective root bridges for the VPN devices connected to the merged site to the selected root bridge. 
     
     
       6. The method of  claim 5 , further comprising:
 bringing down the one of the L2 networks; and 
 bringing up the one of the L2 networks with the selected root bridge after changing the root bridge. 
 
     
     
       7. The method of  claim 1 , further comprising electing a single-active designated forwarder (DF) from the VPN devices connected to the merged site. 
     
     
       8. The method of  claim 7 , wherein the single-active DF is elected using border gateway protocol (BGP) network layer reachability information (NLRI). 
     
     
       9. A network device for preventing broadcast looping in a network, comprising:
 a processor and a memory operably coupled to the processor, the memory having computer-executable instructions stored thereon that, when executed by the processor, cause the processor to: 
 detect a site merge between a plurality of layer 2 (L2) networks using a spanning tree protocol (STP); 
 block a data traffic port connecting the L2 networks in response to detecting the site merge; 
 perform an STP-Ethernet virtual private network (EVPN) handshake, wherein the STP-EVPN handshake comprises:
 notifying a plurality of virtual private network (VPN) devices connected to the merged site of a request to change a root bridge in one of the L2 networks, 
 changing the root bridge in the one of the L2 networks, and 
 receiving acknowledgement after changing the root bridge in the one of the L2 networks; and 
 
 unblock the data traffic port connecting the L2 networks, wherein detecting the site merge between the L2 networks using the STP comprises detecting presence of different root bridges for the L2 networks. 
 
     
     
       10. The network device of  claim 9 , wherein the data traffic port connecting the L2 networks is unblocked after changing the root bridge in the one of the L2 networks. 
     
     
       11. The network device of  claim 9 , wherein the STP-EVPN handshake is performed by exchanging STP messages with the VPN devices connected to the merged site. 
     
     
       12. The network device of  claim 9 , the memory having further computer-executable instructions stored thereon that, when executed by the processor, cause the processor to:
 calculate a new spanning tree for the merged site; and 
 select a root bridge for the merged site. 
 
     
     
       13. A non-transitory computer-readable recording medium having computer-executable instructions stored thereon for preventing broadcast looping in a network that, when executed by a processor, cause the processor to:
 detect a site merge between a plurality of layer 2 (L2) networks using a spanning tree protocol (STP); 
 block a data traffic port connecting the L2 networks in response to detecting the site merge; 
 perform an STP-Ethernet virtual private network (EVPN) handshake, wherein the STP-EVPN handshake comprises:
 notifying a plurality of virtual private network (VPN) devices connected to the merged site of a request to change a root bridge in one of the L2 networks, 
 changing the root bridge in the one of the L2 networks, and 
 receiving acknowledgement after changing the root bridge in the one of the L2 networks; and 
 
 unblock the data traffic port connecting the L2 networks, wherein detecting the site merge between the L2 networks using the STP comprises detecting presence of different root bridges for the L2 networks. 
 
     
     
       14. The non-transitory computer-readable recording medium of  claim 13 , wherein the data traffic port connecting the L2 networks is unblocked after changing the root bridge in the one of the L2 networks. 
     
     
       15. The non-transitory computer-readable recording medium of  claim 13 , having further computer-executable instructions stored thereon that, when executed by the processor, cause the processor to elect a single-active designated forwarder (DF) from the VPN devices connected to the merged site.